The function of a channel diode also called a pseudo-Schottky diode (reference U.S. Pat. No. 6,476,442) is described in FIG. 1. The forward biased current versus voltage curve of a conventional PN diode such as show in FIG. 2 is given by curve 1004 in FIG. 1. A diode offset voltage of about 0.7 volts must be overcome before current begins to flow in the forward biased direction. The current in a PN diode consists of both majority and minority carriers. After the PN diode has carried a forward current, the voltage supporting region contains a mixture of minority and majority carriers and cannot support a reverse voltage until sufficient time has passed for the excess minority carriers to recombine so that a depletion region may reform. This results in the PN junction having a long recovery time when compared to a majority carrier only device.
Current versus voltage curve, 1002, is of a channel diode such as is illustrated in FIG. 3. The channel diode 3000 consists of an NMOS transistor, 3000, with gate shorted to source and body in parallel with source to body PN diode 2000. When the body potential of transistor 3000 begins to rise the source to body offset voltage is reduced and the turn on voltage of transistor 3000 is lowered due to the body effect. The rising source voltage also raises the voltage of the gate causing transistor 3000 to turn on at about 0.4 volts as shown by curve, 1002, in FIG. 1. The lower turn on voltage of the channel diode results in less power loss than the conventional PN diode. In addition, since conduction through the channel of transistor, 3002, in channel diode, 3000, is majority carrier only, recovery time to begin supporting reverse voltages is virtually instantaneous and significantly faster than a PN diode.